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Reminds me of some scientific experiment (I read about it in a paper magazine, it might be on the net) that shown that people were not always able to self-evaluate.

They built a questionary with questions on a specific domain (mathematics ? don’t remember precisely) and a final question that asked people to self-evaluate their skills in that domain :
* those who did not have a clue correctly answered they did not.
* those who knew most to all of the correct questions correctly self-evaluated themselves as “good”
* those who knew something, but not much, shown the biggest gap between their real skills and their self-evaluation : they thought themselves better than they really were.

The interpertation of those results is that the last category know enough about the domain to think they know about it, but they do not know enough to realize that there is a lot they do not know (and that what they know might be approximate or not always true).

Regarding the UFO (Unknown Features of Oracle), mentioned on the referenced blog, I can tell by experience of many New Features courses (which have seasoned DBAs as audience mostly) that there are very many of them. That is not only the case with people, just evaluating Oracle for a week or so like John Scott told about. It is very common also amongst people who use Oracle for years already. If you don’t need a functionality in your daily business – or have found some crude workaround for it – chances are good that you won’t ever notice it and still think you know (almost) everything about Oracle.

I can believe that – I think there’s a lot of pressure on modern DBAs that makes it hard for them to find time to keep learning about new options. Of course there’s also the inertia effect that makes people say: “how did I do this last time”, rather than thinking “I wonder if there’s a good way of doing this in the new release.”